tmk_core/tool/mbed/mbed-sdk/libraries/mbed/targets/hal/TARGET_NORDIC/TARGET_MCU_NRF51822/TARGET_DELTA_DFCM_NNN40/rtc_api.c

   1 /* mbed Microcontroller Library
   2  * Copyright (c) 2006-2013 ARM Limited
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16 #include "rtc_api.h"
  17
  18
  19 #define LFCLK_FREQUENCY         (32768UL)
  20 #define RTC0_COUNTER_PRESCALER  ((LFCLK_FREQUENCY/8) - 1)
  21 #define COMPARE_COUNTERTIME       (691200UL) //86400 x 8
  22
  23
  24 time_t  initTime;
  25
  26 void rtc_init(void) {
  27
  28     NVIC_EnableIRQ(RTC0_IRQn);                                      // Enable Interrupt for the RTC in the core.
  29     //NRF_RTC0->TASKS_STOP =1;
  30     NRF_RTC0->PRESCALER     = RTC0_COUNTER_PRESCALER;               // Set prescaler to a TICK of RTC_FREQUENCY.
  31     NRF_RTC0->CC[0]         = COMPARE_COUNTERTIME;                 // Compare0 after approx COMPARE_COUNTERTIME seconds.
  32
  33     // Enable COMPARE0 event and COMPARE0 interrupt:
  34     NRF_RTC0->EVTENSET      = RTC_EVTENSET_COMPARE0_Msk;
  35     NRF_RTC0->INTENSET      = RTC_INTENSET_COMPARE0_Msk;
  36     NRF_RTC0->TASKS_START = 1;
  37 }
  38
  39 void rtc_free(void) {
  40     // [TODO]
  41 }
  42
  43 /*
  44  * Little check routine to see if the RTC has been enabled
  45  *
  46  * Clock Control Register
  47  *  RTC_CCR[0] : 0 = Disabled, 1 = Enabled
  48  *
  49  */
  50 int rtc_isenabled(void) {
  51     // [TODO] return(((NRF_RTC0->TASKS_START) & 0x01) != 0);
  52 }
  53
  54 time_t rtc_read(void) {
  55
  56     time_t t = initTime;
  57     t += (86400*NRF_RTC0->EVENTS_COMPARE[0]);
  58     t += (int)((NRF_RTC0->COUNTER)/8);
  59     return(t);
  60 }
  61
  62 void rtc_write(time_t t) {
  63     // Convert the time in to a tm
  64
  65     // Pause clock, and clear counter register (clears us count)
  66     NRF_RTC0->TASKS_STOP = 1;
  67
  68     initTime = t;
  69     // Restart clock
  70     NRF_RTC0->TASKS_START = 1;
  71 }